SPC Flavor Summary Steven Gottlieb Indiana University USQCD All - - PowerPoint PPT Presentation

Steven Gottlieb Indiana University

USQCD All Hands Meeting Jefferson Laboratory Newport News, VA April 28, 2017

SPC Flavor Summary

• S. Gottlieb, USQCD AHM, 4/28/17

Introduction

✦ Caveat: This has not been reviewed by the SPC, so

please don’t blame the rest of the SPC for anything you do not like.

✦ Goals:

• Brief summary of 2017 B physics proposals
• Discussion of some of the physics opportunities to pin down the

CKM matrix, test the Standard Model, search for evidence of new physics

3

• S. Gottlieb, USQCD AHM, 4/28/17

Proposals

✦ Determination of |Vcb| from Semi-leptonic Decays

B→D(*) l ν using the Oktay-Kronfeld Action; PI: Gupta, 26 M J-Psi core-hr

✦ Investigation of B→K π l+l- Decays with Lattice QCD; PI:

Leskovec, 18.9 M J-Psi core-hr

✦ Standard Model Parameters and the Search for Physics

Beyond the Standard Model with HISQ; PI: Mackenzie, 87.4 M J-Psi core-hr + 5.7 M BG/Q core-hr

✦ Semi-leptonic B and Bs-decays with charming hadronic

final state; PI: Soni, 17.6 M J-Psi core-hr

✦ The following slides will summarize the goals of each

proposal.

4

• S. Gottlieb, USQCD AHM, 4/28/17

Gupta

✦ Uses Oktay-Kronfeld heavy quark action for b and c

quarks

✦ MILC HISQ ensembles: three lattice spacings and three

values of pion mass at each lattice spacing.

✦ a=0.15, 0.12 fm done on local clusters. Time is for 250

configurations of a=0.09 fm ml/ms=0.1 and physical mass ensembles.

• 2016 allocation used for ml/ms=0.2 ensemble

✦ Use truncated solver method ✦ Aim for 1.0% (1.1%) error for B→D* lν (B→D lν ) form

• factors. Currently, 1.4% (1.2)%.

✦ More about |Vcb| later…

5

• S. Gottlieb, USQCD AHM, 4/28/17

Leskovec

✦ Studying rare flavor changing neutral current decay

B→K π l+l- in region of K*(892)

✦ Uses 2+1 flavor dynamical clover ensemble with

a=0.114 fm and mπ=317 MeV

✦ LHCb found anomalous angular dependence at low q2. ✦ Sensitive probe of beyond standard model physics. ✦ Previously K* treated as a stable particle ✦ Use one large volume (323×96) and several moving

frames

✦ Continuation: about 285 configurations will be analyzed

this year. Would like to get to 800 with new allocation.

6

• S. Gottlieb, USQCD AHM, 4/28/17

Mackenzie

✦ Use 2+1+1 flavor HISQ ensembles; HISQ light valence

quarks, Wilson/clover (w. FNAL interp.) b,c quarks; c quarks treated with HISQ as well for some projects

✦ Six lattice spacings: a≈0.15, 0.12, 0.09, 0.06,0.042, 0.03 fm

✦ Physical light quark mass except for 0.03 fm ensemble

✦ Test CKM unitarity with broad range of decays:

✦ B→π l ν, B→D(*) l ν, Bs→Ds(*) l ν, K→π l ν, D→π(K) l ν ✦ neutral B meson mixing ✦ B→τ ν, B→D(*) τ ν, B→K(*) l+l- ✦ Decay constants for pseudoscalar and vector mesons ✦ charm and bottom quark masses, αs

✦Aim for better precision than asqtad results

7

• S. Gottlieb, USQCD AHM, 4/28/17

Soni

✦Using Mobius domain-wall 2+1 flavor ensembles ✦Seven ensembles with 0.114 fm > a > 0.711 fm, one

with physical mass pion

✦Relativistic heavy quark (RHQ) action ✦B→D(*) l ν, Bs→Ds(*) l ν to determine |Vcb| ✦Light and strange quark propagators are already

archived.

✦Will run on two 483×96 ensembles with a=0.11 and

0.07 fm, with pion mass 138 and 234, respectively.

✦Three other ensembles already analyzed.

✦Will later compute B meson mixing, & decay constants

8

• S. Gottlieb, USQCD AHM, 4/28/17

Kobayashi & Maskawa

✦ Won 2008 Nobel prize for realization that with three (or

more) generations can have CP violation, which might explain baryon asymmetry of Universe.

9

KEK photo from nobelprize.org

• S. Gottlieb, USQCD AHM, 4/28/17

CKM Matrix

✦ Some relevant processes listed under each element

10

• S. Gottlieb, USQCD AHM, 4/28/17

CKM Matrix II

✦ CKM matrix is unitary.

• Each row and column is a (complex) unit vector.
• Each row (column) is orthogonal to the other rows (columns).

✦ Violations of unitarity are evidence of non-standard

model physics.

✦ If two different processes are used to determine an

element of the matrix and they do not agree, that is evidence for new physics.

✦ LQCD input for decay constants and form factors is

needed to determine elements of CKM matrix

11

B(D(s) → `⌫`) = G2

F |Vcq|2⌧D(s)

8⇡ f 2

D(s)m2 `mD(s)

1 − m2

`

m2

D(s)

!2

• S. Gottlieb, USQCD AHM, 4/28/17

First Row: Light Quarks

✦ Processes involving only light quarks test first row unitarity

12

leptonic semileptonic

• S. Gottlieb, USQCD AHM, 4/28/17

fπ and fK

• Light decay

constants as summarized by FLAG

• Some calcs. use fπ

to set the scale so fewer results on left

• Ratio of decay

constants is easy to calculate and used to test unitarity

13

• S. Gottlieb, USQCD AHM, 4/28/17

fπ/fK

• Light decay

constant ratio summarized by FLAG

• From experimental

measurement:

14

• Vus

Vud

• fK±

fπ± = 0.2758(5)

• S. Gottlieb, USQCD AHM, 4/28/17

K semileptonic decay

✦ Semileptonic decays have three-body final states, so

there is one kinematic variable, usually denoted q2 , which is momentum transfer to the leptons.

✦ To extract |Vus| we just need f+(0) as experiment tells us ✦ From FNAL/MILC with 2+1+1 flavors PRL 112, 112001 (2014),

arXiv:1312.1228 (0.34 % error)

15

pK = p⇡ + q` + q⌫

q = q` + q⌫ |Vus|f+(0) = 0.2163(5) f+(0) = 0.9704(24)(22)

• S. Gottlieb, USQCD AHM, 4/28/17

f+(0) for Kaon Decay

• FLAG averages for

Kaon decay constant at q2=0

• Only one value for

Nf=2,2+1+1

• Two values for

Nf=2

• Next, we look at

unitarity test

16

• S. Gottlieb, USQCD AHM, 4/28/17

0.9484 0.9488 0.9492 0.9496

|Vud|

2 0.0492 0.0496 0.05 0.0504 0.0508

|Vus|

2

First Row Unitarity Test

• Black line is unitarity
• Vertical band is from

nuclear β decay (LQCD independent)

• Angled band is from

leptonic decays

• Horizontal band is from

semileptonic K decay

• Some tension between

the two types of decay for 2+1+1.

• Can we reduce

semileptonic error? 1611.04188

17

FNAL/MILC, Phys.Rev. D90 (2014) 7, 074509 arXiv:1407.3772

• S. Gottlieb, USQCD AHM, 4/28/17

First Row Unitarity (FLAG)

• Preliminary FLAG3

results for 2+1 and 2+1+1 flavors

• Matrix elements not

squared here

• Dotted line is

unitarity

• 2+1 flavors has

larger error and consistent with unitarity

18

• S. Gottlieb, USQCD AHM, 4/28/17

|Vus| & |Vud| Summary

19

• plot from FLAG
• squares leptonic
• triangles

semileptonic

• good agreement w.

2+1 flavors, some tension for 2+1+1

• note tension

between τ decay results and π and K decays

• S. Gottlieb, USQCD AHM, 4/28/17

Second Row: Charm Quark

✦ Processes involving charm quark test second row unitarity

20

leptonic semileptonic

• S. Gottlieb, USQCD AHM, 4/28/17

Charm Decay Constants

• Note improvement
• f precision from

initial 2005 2+1 flavor results to current 2+1+1 flavor results.

• FLAG3 averages

should be quite similar with slightly smaller errors

21

200 250 300 ALPHA Lat’13 ETM 09 ETM 11 ETM 13 FNAL/MILC 05 HPQCD 07 HPQCD 10 FNAL/MILC 11 HPQCD 12 χQCD Lat’13 FNAL/MILC Lat’12 ETM Lat’13

This work

MeV

fD fDs

Nf = 2 Nf = 2+1 Nf = 2+1+1

fD+ = 212.6(0.4)(+1.0

−1.2) MeV

fDs = 249.0(0.3)(+1.1

−1.5) MeV

FNAL/MILC, Phys.Rev. D90 (2014) 7, 074509 arXiv:1407.3772

• S. Gottlieb, USQCD AHM, 4/28/17

1.1 1.2 1.3 1.4 ALPHA Lat’13 ETM 09 ETM 11 ETM 13 FNAL/MILC 05 HPQCD 07 FNAL/MILC 11 HPQCD 12 FNAL/MILC Lat’12 ETM Lat’13

This work

fDs / fD

Nf = 2 Nf = 2+1 Nf = 2+1+1

Charm Decay Constant Ratio

• Once again, note

remarkable improvement over the past decade

22

FNAL/MILC, Phys.Rev. D90 (2014) 7, 074509 arXiv:1407.3772

fDs/fD+ = 1.1712(10)(+29

−32)

• S. Gottlieb, USQCD AHM, 4/28/17

FLAG Charm Decay Constant Ratio

• Once again, note

remarkable improvement over the past decade

• FLAG 1.1716(32) for

2+1+1 flavors

23

fDs/fD+ = 1.1712(10)(+29

−32)

• S. Gottlieb, USQCD AHM, 4/28/17

Extraction of Vcd & Vcs

✦ The experimental results for charm meson leptonic

decays are summarized by the Heavy Flavor Averaging Group (HFAG):

✦ Experimental error is 2.1-4.3%. ✦ Using decay constants from LQCD, we get CKM matrix

elements:

✦ Errors are lattice, experiment, and structure dependent

electromagnetic, respectively.

24

fD|Vcd| = 46.40(1.98)MeV, fDs|Vcs| = 253.1(5.3)MeV

|Vcd| = 0.217(1)(5)(1), |Vcs| = 1.010(5)(18)(6)

• S. Gottlieb, USQCD AHM, 4/28/17

0.044 0.046 0.048 0.05

|Vcd|

2 0.95 1 1.05

|Vcs|

2

Second Row Unitarity

• Black line is unitarity
• Horizontal blue band is Ds

leptonic decay

• Vertical green band is D+

leptonic decay

• Note the ≈1.8 σ tension

with unitarity

• Fajfer et al,. PRD91, (2015)

094009 bound new physics

• Fewer results for

semileptonic D meson decays

• Expt. error dominant now.

25

FNAL/MILC, Phys.Rev. D90 (2014) 7, 074509 arXiv:1407.3772

• S. Gottlieb, USQCD AHM, 4/28/17

D semileptonic result

✦ Interestingly, there is a new BaBar paper, PRD91,

052022(2015), on semileptonic D decay that uses HPQCD result.

✦ It yields |V_{cd}| = 0.206 \pm 0.007_{\rm exp} \pm

0.009_{\rm LQCD}.

✦ Adding errors in quadrature 0.206 (11) compared with

• ur leptonic decay result of 0.217(5).

✦ Their central value is two of our sigma below our result,

but our result is only one of their sigmas high.

26

• S. Gottlieb, USQCD AHM, 4/28/17

B Meson Decays

✦ Leptonic and semileptonic decays studied in LQCD ✦ Rare decays involving flavor changing neutral currents

(FCNC) also studied

• FCNC vanish at tree level in Standard Model, so a good place to

look for new physics

• Some tension between recent SM prediction from LQCD and

LHCb measurements

• Alternative to B meson mixing for determining |Vtd| and |Vts|

27

• S. Gottlieb, USQCD AHM, 4/28/17

B Meson Leptonic Decays

• FLAG3 will have only

minor updates to these results

• RBC/UKQCD 2+1
• ETM 2+1+1 (plotted)
• both have large errors
• For 2+1 and 2+1+1

flavors errors about 2%

• fB=190.5(4.2) MeV,

fBs=227.7(4.5) MeV for 2+1 flavors (2013)

28

• S. Gottlieb, USQCD AHM, 4/28/17

|Vub| from FLAG2

• Large errors for

leptonic decays from experiment (25%)

• Semileptonic decays

give smaller value

• Tension between

exclusive and inclusive results

• Plot from T. Vladikas

arXiv:1509.01155

• Belle II will improve

B→τν measurement (5% error expected)

29

• S. Gottlieb, USQCD AHM, 4/28/17

Exclusive B Decay Update

✦ FNAL/MILC updated form factors for semileptonic

decays PRD 92, 014024 (2015),arXiv:1503.07839

✦ FLAG: ✦ New FNAL/MILC result ✦ This result decreases, but does not eliminate tension

between exclusive and inclusive results.

✦ Next slide also includes Lambda baryon decay result

30

|Vub| = 3.37(21) × 10−3, Nf = 2 + 1; BaBar |Vub| = 3.47(22) × 10−3, Nf = 2 + 1; Belle |Vub| = 3.72(16) × 10−3, Nf = 2 + 1; BaBar&Belle

• S. Gottlieb, USQCD AHM, 4/28/17

Updated Semileptonic |Vub|

31

3.2 3.6 4.0 4.4

|Vub| × 10

3

UTFit 2014, CKM unitarity BLNP 2004 + HFAG 2014, B → Xulν Detmold et al. 2015 + LHCb 2015, Λb → plν HPQCD 2006 + HFAG 2014, B → πlν Imsong et al. 2014 + BaBar12 + Belle13, B → πlν RBC/UKQCD 2015 + BaBar + Belle, B → πlν Fermilab/MILC 2008 + HFAG 2014, B → πlν This work + BaBar + Belle, B → πlν

PRD 92, 014024 (2015),arXiv:1503.07839

Lattice error now comparable to experimental error.

• S. Gottlieb, USQCD AHM, 4/28/17

|Vcb|

✦ Exclusive calculations of B→D* l ν and B→D l ν yield

Vcb

✦ Experimental error dominant for B→D l ν (3.9% vs 1.4%) ✦ Again, tension between exclusive and inclusive results

PRD 92, 034506 (2015), arXiv:1503.07237 [hep-lat]

✦ But two exclusive decay modes consistent

32

36 37 38 39 40 41 42 43 44

|Vcb| × 10

3

Gambino & Schwanda ’13, B → Xc inclusive Fermilab/MILC ’14 + HFAG ’14, B → D

*, w = 1

Fermilab/MILC ’15 + HFAG ’14, B → D, w = 1 Fermilab/MILC ’15 + BaBar ’09, B → D, w ≥ 1

• S. Gottlieb, USQCD AHM, 4/28/17
• 0.02

0.02

z(q

2

,topt)

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

f0(q

2)

FNAL/MILC 15C HPQCD 15 3-parameter BCL fit

B→D l ν form factor

• Two results with 2+1

flavors both on MILC asqtad ensembles.

33

Enrico Lunghi

/25

Moriond QCD 2017

36 38 40 42 44 3.0 3.5 4.0 4.5

|| ⨯ || ⨯

17

Vub and Vcb: exclusive vs inclusive

Exclusive: Inclusive [PDG]:

[FLAG] [PDG+FLAG] [FLAG] [FLAG] [PDG]

|Vub|B→Xu`⌫ = 4.49(16)(+16

−18) × 10−3

|Vcb|B→Xc`⌫ = 42.2(0.7) × 10−3

|Vub|B→⇡`⌫ = 3.73(14) × 10−3 |Vub|B→⌧⌫ = 4.33(72) × 10−3 |Vcb|B→D`⌫ = 40.1(1.0) × 10−3 |Vcb|B→D∗`⌫ = 39.27(56)(49) × 10−3 |Vub/Vcb|Λb→(p,Λc)`⌫ = 0.083(6)

B → ⇡`⌫

B → τν

Λb → p`⌫ Λb → Λc`⌫

B → D`⌫ B → D∗`⌫

inclusive

pexcl=0.27 68%CL 95%CL

[Detmold, Lehner, Meinel]

The overall tension between all these determinations is 3.2 σ Future progress B→D* form factor: q2 dependence and use


• f BCL/BGL parametrization

Bs→Klν

[Bigi, Gambino, Schacht 1703.06124] [Grinstein, Kobach 1703.08170] [Berlochner et al. 1703.05330]

uses CLN parametrization [Caprini, Lellouch, Neubert 9712417]

B → D∗`⌫

using the new Belle result 1702.01521

• S. Gottlieb, USQCD AHM, 4/28/17

Ken Lane’s List from LHCb

✦ 25%< SM (2.6σ) ✦ Independently, branching ratio 30%

<SM (2σ)

✦ Earlier results for electron mode consistent with SM

• Lepton nonuniversality may not demand much more from LQCD,

i.e., BSM physics will change Wilson coefficients. (pheno ms.)

✦ angular distribution differs from SM by

2.9σ in two bins. Theoretical error questioned.

• We have not done this decay. (Not gold plated…)

✦ branching ratios jointly measured by

CMS and LHCb …

34

B+ → K+µ+µ−/B+ → K+e+e− B+ → K+µ+µ− B0 → K∗0µ+µ− B(s) → µ+µ−

• S. Gottlieb, USQCD AHM, 4/28/17

✦ Nature: doi:10.1038/nature14474 (we’re cited)

35

B(s) → µ+µ−

• S. Gottlieb, USQCD AHM, 4/28/17

CMS+LHCb II

✦ 2D contour plot of branching ratios

• Bs too small by 1σ
• B too big by ≈2σ

36

• S. Gottlieb, USQCD AHM, 4/28/17

CMS+LHCb II

✦ Individual contour plots

37

• S. Gottlieb, USQCD AHM, 4/28/17

Rare B Decays

✦ FNAL/MILC has recently calculated form factors

needed for several rare decays that require flavor changing neutral current.

✦ Good place to look for new physics ✦ Some tension between SM prediction and recent LHCb

measurement

38

• S. Gottlieb, USQCD AHM, 4/28/17

Rare B Decays II

• LHCb measurement is smaller than SM prediction in 3 of 4 bins. 1.7 σ

tension.

• arXiv:1510.02349

39

✦ Rare decays depend on |Vtq| with q=d or s ✦ The same elements of CKM matrix can be determined

from B-meson mixing

✦ New |Vts| is 1.4 σ below that from mixing with smaller

error

✦ Values of |Vtd| are comparable ✦ LQCD will help improve both determinations

• S. Gottlieb, USQCD AHM, 4/28/17

Rare B Decays III

40

|Vtd| = 7.45(69) × 10−3, |Vts| = 35.7(1.5) × 10−3

|Vtd| = 8.4(6) × 10−3, |Vts| = 40.0(2.7) × 10−3

• S. Gottlieb, USQCD AHM, 4/28/17

R(D)

0.2 0.4 0.6

R(D*)

0.3 0.4

SM

σ 1 σ 2 σ 3 σ 4 σ 5

R(D) and R(D*)

• BaBar: PRD88,

072012 (2013)

• FNAL/MILC:

PRL109, 071802, (2012)

• R(D): 2.0σ
• R(D*): 2.7σ
• Together: 3.4σ
• all BaBar’s values
• However, no

agreement is 2H model

41

• S. Gottlieb, USQCD AHM, 4/28/17

0.2 0.4 0.6 0.8 1

R(D)

0.2 0.4 0.6 0.8 0.2 0.4 0.6 0.8 1

R(D)

0.2 0.4 0.6 0.8

t

0.2 0.4 0.6 0.8 1

R(D*)

0.2 0.3 0.4

t

0.2 0.4 0.6 0.8 1

R(D*)

0.2 0.3 0.4

R(D) and R(D*) II

• BaBar’s comparision

with two Higgs doublet model predictions

• x-axis should be

tan(β)/MH

42

• S. Gottlieb, USQCD AHM, 4/28/17

0.2 0.4 0.6 0.8 1 0.1 0.2 0.3 0.4 0.5 tanβ/MH+ (GeV-1) 0.2 0.4 0.6 0.8 1 0.1 0.2 0.3 0.4 0.5 tanβ/MH+ (GeV-1) 1 σ 2 σ BaBar ’12 2HDM II (This work)

• We slightly improve

agreement between BaBar result and standard model.

43

• S. Gottlieb, USQCD AHM, 4/28/17

Introduction

✦ Goal is quick summary of some of the places where

there is a hint of beyond the standard model physics.

• Emphasis on where lattice QCD might have an impact.
• Many graphs from our recent papers.

✦ Obvious non-lattice:

• neutrino masses and mixing
• dark matter
• dark energy

✦ Muon g-2

• Many talks on this subject, so just point out it is one of the most

significant anomalies.

2